Under the initial proposal, backers were asking Hillsborough County taxpayers to front as much as $24 million to pay for docks, parking and even the boats. But the county is pressing New Albany, Ind.-based HMS Ferries Inc. to pay for those capital costs in exchange for a possible operating subsidy to cover some portion of what the company does not recoup in fares.

County officials say the initial proposal puts too much of the risk on taxpayers at a time when government coffers still face stark shortfalls in tax revenues to pay for things such as roads, drainage and other needs.

"The good part of this approach is, if it doesn't work we're not stuck with a bunch of boats that we don't know what to do with," said County Administrator Mike Merrill. The gives the county the ability to pull the plug if needed, he said.

Former county Commissioner Ed Turanchik, a longtime advocate of public mass transit, first pitched the high-speed ferry idea publicly in May. He's now a lawyer with the Akerman Senterfitt firm, which engaged HMS Ferries to consider opening shop on Tampa Bay.

The service here would be built around rush-hour commuter shuttles between MacDill Air Force Base and southern Hillsborough County, where some 5,300 military families live. Catamaran vessels with an initial capacity of 250 to 300 people could be used at other hours to ferry passengers between Tampa and downtown St. Petersburg, or for special events.

A recent survey of MacDill employees showed strong support for the concept, said Ramond Chiaramonte, executive director of the Hillsborough Metropolitan Planning Organization, which commissioned the survey. He was not immediately able to provide a copy of the results.

"I think that it's exciting that an international company thinks that this is a workable thing to do," Chiaramonte said. "It's time we got out of thinking about transportation as only roads. I think this is a good, not terribly expensive way to do that."

Turanchik and representatives of HMS got a warm reception from elected officials and civic leaders when they unveiled their concept. But county commissioners, who are being asked to contribute the bulk of the tax dollars, at least initially, have expressed skepticism at the potential asking price.

Some continue to express interest in the idea, but are not sure it is workable in the near term. Voters in Hillsborough County have not been enthusiastic to back taxpayer supported transit, as evidenced by the 2010 ballot box defeat of a proposal to raise sales taxes primarily for more public buses and local commuter rail.

"There's a will here to try to make it work, but it's got to be advantageous to the public," said Commissioner Sandy Murman, who has been among the most actively engaged elected officials in talks. "I'm not sure there's a will to put $8 million into it."

That's one figure that has been floated as the initial county investment under the original pitch, though Turanchik said most numbers associated with the deal are fluid.

Merrill said the project may work best as a pilot initially to see if the interest expressed in surveys translates to riders. Ultimately, he said, the analysis of the project's merits will be based on high bars that ensure any public investment is protected.

He, for one, wants to see whether ferry service would attract enough riders to make a true dent in traffic in southern Hillsborough – enough so that it might mitigate the need for road widenings.

Turanchik said he takes heart in the fact that the county has been willing to at least negotiate.

"I think there's pretty much broad-based support for the project," Turanchik said. "But it's got to be done in the context of the county's budgetary realities. I think people are trying to figure that out."